Flexural strength

About: Flexural strength is a research topic. Over the lifetime, 52123 publications have been published within this topic receiving 846504 citations. The topic is also known as: bending strength & modulus of rupture.

Effect of water storage on the flexural properties of E-glass and silica fiber acrylic resin composite.

Abstract: PURPOSE The aim of this study was to determine the effect of water on the flexural properties of fiber-reinforced denture base polymers. MATERIALS AND METHODS Continuous woven silanized electrical glass, or E-glass, fibers and woven silica fibers were used to reinforce heat-cured and autopolymerized denture base polymers. Fibers were oriented at a 45-degree angle to the long axis of the test specimens. Control specimens were unreinforced. Dry test specimens and those stored in water for up to 48 weeks were tested with a three-point loading apparatus. The surfaces of the fibers of the test specimens stored dry or 48 weeks in water were analyzed with a scanning electron microscope to evaluate the degree of adhesion between fibers and polymer matrix. RESULTS The ultimate transverse strength of unreinforced and reinforced denture base polymers decreased during 48 weeks' storage in water (P < 0.05, one-way analysis of variance, n = 5), and most of this reduction occurred during the first 4 weeks of storage in water. The flexural modulus of the unreinforced test specimens decreased significantly (P < 0.001), whereas there was less, if any, change in the flexural modulus of the fiber-reinforced test specimens. Scanning electron microscopic examination revealed no differences in adhesion of E-glass fibers to the polymer matrix when the specimens stored in water were compared with those stored by. Reduced adhesion between the silica fibers and matrix was observed after 48 weeks' storage in water. CONCLUSION The results of this study suggest that the ultimate transverse strength of the E-glass fiber-reinforced test specimens decreased 14% and that of the silica fiber-reinforced test specimens decreased 36% after 48 weeks of storage in water.

Compressive response and failure of fiber reinforced unidirectional composites

Abstract: The compressive response of polymer matrix fiber reinforced unidirectional composites (PMC's) is investigated via a combination of experiment and analysis The study accounts for the nonlinear constitutive response of the polymer matrix material and examines the effect of fiber geometric imperfections, fiber mechanical properties and fiber volume fraction on the measured compressive strength and compressive failure mechanismGlass and carbon fiber reinforced unidirectional composite specimens are manufactured in-house with fiber volume fractions ranging over 10∼60 percent Compression test results with these specimens show that carbon fiber composites have lower compressive strengths than glass fiber composites Glass fiber composites demonstrate a splitting failure mode for a range of low fiber volume fractions and a simultaneous splitting/kink banding failure mode for high fiber volume fractions Carbon fiber composites show kink banding throughout the range of fiber volume fractions examined Nonlinear material properties of the matrix, orthotropic material properties of the carbon fiber, initial geometric fiber imperfections and nonuniform fiber volume fraction are all included in an appropriate finite element analysis to explain some of the observed experimental results A new analytical model predictionof the splitting failure mode shows that this failure mode is favorable for glass fiber composites, which is in agreement with test results Furthermore, this modelis able to show the influence of fiber mechanical properties, fiber volume fraction and fiber geometry on the splitting failure mode

Behavior of eccentrically loaded concrete-filled steel tubular columns

Abstract: Beam columns of concrete-filled steel tubular (CFT) columns are designed using a design formula established by the Architectural Institute of Japan (AIJ). However, the scope of the formula in the current AIJ standard is limited to ordinary material strengths, and a rational mathematical model which makes it possible to reproduce load-deformation behavior in CFT columns has not yet been established. The main objectives of this research were to investigate the effect of higher material strengths on the flexural behavior and to create mathematical models of the steel tube and filled concrete. Adequate study of the effects of the section shape, diameter (width)-to-thickness ratio, and the combination of strengths of the steel tube and filled concrete was included in the scope of this investigation. Based on the experimental results of 65 eccentric compression tests, an analytical model for the restoring force characteristics of the flexural behavior of CFT columns is proposed, and is found to reproduce experi...